Abd al-Rahman bin Abi Layla (may Allah have mercy on him) said: Sayyiduna Ali (may Allah be pleased with him) used to pay the zakah on the wealth of the sons of Sayyiduna Abu Rafi' (may Allah be pleased with him). When Sayyiduna Ali (may Allah be pleased with him) handed that wealth over to them, they found it less, and they said: This wealth is short. Sayyiduna Ali (may Allah be pleased with him) said: Do you think that wealth would be with me and I would not pay its zakah?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7344